Many different folding hairbrushes particularly designed to be unobtrusively stowed in a pocket or the like of a user have been proposed. None of the proposed folding brushes have, to my knowledge, been produced on a large scale basis. The proposed folding brushes have probably not been sold on a large scale basis because, inter alia, the problems associated with such brushes have not seemingly been studied with sufficient care.
The typical prior art folding brush has included a case having parallel first and second walls respectively having first and second interior faces spaced from each other to form a cavity. The first wall includes a matrix of cylindrical slots extending between the first face and a third face on the exterior of the first wall. A frame is slid along a longitudinal axis in the cavity between first and second longitudinal positions where the frame is locked. Multiple bristle tufts, each having a longitudinal axis, are mounted on the frame. As the frame slides between the first and second longitudinal positions, the longitudinal axes of the tufts rotate together from a first angle displaced from the frame longitudinal axis to a second angle approximately at right angles to the longitudinal axis.
In one proposed structure, the bristle tufts are positioned on the frame and the matrix of slots is arranged so each of the bristle tufts is in a separate one of the slots. The matrix is arranged so that the bristle tufts in adjacent rows are displaced to be in offset columns, such that the bristle tufts in alternate rows are in aligned columns and vice versa. In other words, the bristle tufts in even numbered rows are in aligned columns, while the bristle tufts in odd numbered rows are in aligned columns different from the bristle tufts in even numbered rows. Such a configuration enables the bristle tufts to be packed compactly in such a manner as to preclude interference between each other as the tufts are rotated so they extend from and are retracted in the case.
In analyzing the prior art brushes having folding bristle tuft matrices, I have found that several problems are extant. The bristles have a tendency to become frayed if any bristle in a particular tuft or if a unifilar element forming a bristle tuft extends beyond the third face, i.e., outside of the slot in which it is located, while the frame is in the retracted position. Fraying of the bristles has a tendency to enlarge the diameter of a particular tuft. My experiments have revealed that such enlargement must be avoided because such bristles have a tendency to catch on the slot when the bristle tufts are driven between the retracted and expanded position, i.e., from the first angle to the second angle. Catching of one bristle in a particular tuft or a single unifilar element forming a tuft may prevent rotation of the bristles or tufts or of the entire bristle matrix. Catching of the bristles causes additional fraying, causing the entire process to become regenerative. A frayed tuft is ineffective and can have deleterious effects on the hair of a user. It is also desirable to prevent the tips of the bristles from protruding beyond the case to enable the structure to have a neat appearance, and to be smooth to the touch. In addition, if the bristles protrude beyond the case, the bristles have a tendency to tangle with objects in places where the brush is stored, for example, a pocketbook, pocket, suitcase, wash kit, glove compartment, etc.
It is, accordingly, an object of the present invention to provide a new and improved folding brush.
Another object of the present invention is to provide a new and improved folding brush having bristle tufts arranged so that no bristles extend outside of slots in which the tufts are located while the bristles are in a retracted position in a case therefor.
An additional object of the invention is to provide a new and improved folding brush wherein the tendency of bristles in the brush to fray while the bristles are in a retracted position is avoided.
Still an additional object of the invention is to provide a new and improved folding brush wherein bristle tufts are held in place in slots while the brush is in a retracted, inoperative position, and a casing for the brush has a relatively small volume so that the brush can be stowed unobtrusively while not in use.